Conversion of creosote



Patented Feb. 2, 1943 UNITED STATES ran are CONVERSION or cnnoso'rs NoDrawing. Application July 13, 1940, Serial No. 345,443

2 Claims.

This invention relates to the joint production of solvents and woodpreservatives from creosote.

Creosote is a wood preserving distillate recovered from tars of aromaticcontent and includes distillates of various boiling ranges, as forinstance any of the creosotes noted in the following tabular data:

WOOD PRESERVING IMPREGNANTS Specification 1. A. W. P. A.

a-up to 210 C., not more than 5% bup to 235 0., not more than 25% 2. A.W. P. A.

a-up to 210 0., not more than 1% b-up to 235 C., not more than c--up to355 C'., not less than 65% 3. A. W. P. A.

a-up to 235 C., not more than 1 bup to 300 0., not more than Mi cup to-355 0., not less than 45% 4. A. W. P. A.

a--up to 210 (3., not more than 8% b-up to 235 0., not more than 35% W.P. A.

a-up to 210 C., not more than 10% b-up to 235 C., not more than 35% 6.A. W. P. A.

a-up to 210 0., not more than 5% bup to 235 C., not more than '7.Prussian Ry.

a--up to 150 0., not more than 3% b-up to 200 (3., not more than 10% cupto 235 C., not more than 8. N. P. V. 8: L. A.

'a--5% at 162 C.

b97% at 270 C. 9. S. P. S. S. O.

a5% at 137 C. b95% at 257 C. 10. N. S. S. O.

tt--I. B. P., 150 C. b5% at 205 C. c95% at 292 C.

By the process of the present invention, creosote is treated withhydrogen whereby to produce solvents of enhanced solvency and woodpreservatives of added toxicity.

By the term enhanced solvency is meant the solvents of the presentinvention have a higher solvency than solvents extant of comparableboiling range; by the term added toxicity is meant that the woodpreservatives of the present invention are higher in toxicity than thestarting material.

Creosotes, the starting materials of thepresent invention, arecharacterized by a content of oxygenated organic compounds. Theinvention provides a process for the conversion of creosotes intosolvents and wood preservatives, the conversion being brought about bysubjecting the starting materials to the action of hydrogen .while underthe influence of catalytic material adapted to influence thedecomposition of oxygenated organic compounds contained therein.

It was formerly discovered that creosotes containing oxygenatedcompounds could be subjected to the action of hydrogen whereby toconvert them to solvents and newly formed wood preserving oils, thenewly formed wood preserving oils being characterized by induced toxicproperties. It'is now discovered that the induction of toxicity in thenewly formedwood preserving oils can be enhanced by effecting theconversion in the presence of catalytic material adapted to decomposesaid oxygenated organic compounds.

The following examples will show modes of practicing the presentinvention.

Example 1.A high residue creosote boiling substantially 5% at 210 C. andless than 35% at 235 C. was subjected to the action of hydrogen at 420C. and 300 atmospheres pressure. Catalyst used consisted of molybdenumsulfide and tin chloride. Time of reaction was substantially one hour.The beneficiated creosote was removed from the reaction zone andinspected and was found to have a considerable percentage distillingbetween C. and 205 C. and said percentage had a solvency in excess ofsolvents currentlyon the market having comparable boiling range orranges. The beneficiated creosote was distilled up to-205 C. with thedistillate serving as a solvent of the present invention and the residuetherefrom serving as the wood preservative of added toxic value ascompared to the starting material. The induction of toxicity wasenhanced because of the presence of the catalytic material thatinfluenced decomposition of oxygenated compounds while under theinfluence of hydrogen.

The point of separation of said solvents and Wood preservatives is notinflexible inasmuch as solvents of commercial acceptance have variousend points and wood preserving oils of known and publishedspecifications are or varying'initiai boiling points. Thus, inasmuch asthe end points of the solvents of the present invention correspondsubstantially to the initial boiling points of the wood preserving oilsof the present invention, it is obvious that the point of separation maybe varied as desired. As an illustration in the tabular data shown beloware solvents and wood preservatives of accepted and publishedspecifications, their end points and initial boiling points,respectively,

SOLVENTS Identification: End point Benzol 120 C. Toluol 150 C. Highflash naphtha 200 C.

Heavy naphtha above 200 C.

Woon PRESERVATIVES Identification: Initial point A. W. P.A at 210 C. A.W. P. A 1% at 210 C. A. W. P. A 1 at 235 C. A. W. P. A at 210 C.Prussian Ry 3% at 150 C. N. S. S. O 150 C. S. P. S. S. O 92 C.Carbolineum 270 C.

Thus, it will be seen that, among other things, the present process isadapted to provide treatment of cresote with hydrogen, as heretoforeexplained, whereby to provide a newly induced low boiling point whichcomprises the initial boiling point of the solvent, and said initialboiling point may be controllably held at any point, as for instance:

SoLvENrs Identification: Initial point Benzol 78 C. Toluol 100 C. Highflash naphtha 150 C. High boiling crudes 175 C. Heavy naphtha 150 C.Plasticizers 160 C. and above Or, solvents of special nature may beproduced, as for instance solvents having lower initial boiling pointsthan noted above.

The initial or low boiling point of the overall beneficiated creosote iscontrolled by intensity of process controls. Controls of lesserintensity producing higher initial boiling points and controls ofgreater intensity producing lower initial boiling points, for a givenperiod of treatment.

Light tars of aromatic content derived from petroleum, or fractionsthereof, because of their inordinately low carbon, low specific gravityand viscosity, are herein considered the equivalent of creosote;however, because of, at times, their inordinately high initial boilingpoint, recourse must be had for induction of wider ranges, as forinstance by longer periods of treatment.

Example 2.A petroleum aromatic tar, Conradson carbon of substantially 7,specific gravity substantially 1 and initial boiling point of in theorder of 250 C. is subjected to the action of hydrogen while contactinga catalyst containing a material selected from the group consisting ofhalides, halogens, and derivatives thereof. Temperature of reaction was400 C., pressure 200 atmospheres. Operation is continued until a lowboiling point of substantially 200 C. is induced. The beneficiatedmaterial is cut at 235 C. to provide the solvent as the lower boilingfraction and the wood preserver of enhanced toxic value as the higherboiling fraction.

Example 3.A creosote, for example a coal tar creosote derived from hightemperature coke oven tar, and having little or no residue above 355 C.,is subjected to the action of hydrogen while flowing said creosotethrough a reactor, at a temperature chosen from between 300 C. to 600 C.and the flow of hydrogen or hydrogen containing gas less than 12,000cubic feet per barrel of creosote, pressure chosen from between 20-600atmospheres, and for such a length of time that the initial boilingpoint of resultant beneficiated creosote is in the order of C., orlower; catalyst employed included a material selected from the groupconsisting of halides, halogens, and derivatives thereof. Thebeneficiated creosote is distilled to an upper limit of 375 C., ifdesired, if and when this high boiling point exists after treatment.However, distillate may be recovered by distillation to the point whereno residue results in the distillate at 355 C. whereby to provide in thefractions boiling between 200 C. and 355 C. a wood preservative ofenhanced toxic properties; also to provide a solvent boiling between theinitial boiling point and 200 0. However, the product withoutdistillation may be used.

Example 4.Another mode of practicing the present invention is theproduction of solvents within the range of substantially C. and 290 C.by treatment of creosote as hereinafter set forth. A creosote, as forinstance, one boiling substantially between 235 C. and 350 C., or havingsome residue above 350 C. is subjected to the action of hydrogen whilecontacting a catalytic material composed of tin chloride and iodoform;flow of hydrogen in excess of 2,000 cubic feet per barrel feed, pressure225 atmospheres, and for such a length of time as to produce in theproduct flowing from the reactor no substantial percentage boiling below190 C. The beneficiated material is then distilled to an upper limit, asfor instance to 280 C., the distillate serving as the superior solventof the present invention, and the residue the wood preservative ofenhanced toxic properties. The solvent, that is to say, the portionboiling substantially 190 C. to substantially 290 C. may be fractionatedto provide various solvents, including high boilers, having plasticizingproperties. The wood preservative resulting from said fractional cut maybe used as such, or refined by distillation with residue therefrom beingrecycled or utilized as an article of commerce, as for instance a binderor plasticizer of enhanced value. The wood preservative because of itsboiling range may be used as a substitute for carbolineums.

For use in conjunction with aforenamed catalytic material, other andhydrogenating catalysts may be employed. Especially effective are thoseof the eighth and sixth periodic groups, as for instance oxides andsulfides, separately or in admixture. Especially efiective are theoxides and/or sulfides of molybdenum, tin, vanadium, tungsten, cobalt,or the like; promoted or not; supported or not, as for instance on gels;in admixture with other substances eifective in hydrogenation, or not.

Pressures of in the order of 200 atmospheres and above are the preferredoperating pressures at present; however, lower pressures may be used forpracticing the invention. The preferred temperatures are chosen from therange above 300 C., however, lower temperatures may be used.

By the term beneficiated is meant the starting material at least oncesubjected to the action of hydrogen in accordance to the presentinvention.

Starting feeds include all creosotes, and their equivalents, refined inany manner, as for instance by hydrogen, and at times such is preferred.

When carrying on the present process in a continuous manner, hydrogenflows are always held in excess of 2,000 cubic feet per barrel creosotetreated, preferably, at times, in excess of 10,000 cubic feet, accordingto desired results.

In continuous practice the reaction zone may consist of a singlereactor, a series thereof, a parallelism thereof, including amultiplicity thereof. The end products of the present invention may beproduced by passing the starting material to a reactor for more or lessrefining reaction, thereafter with or without releasing gas pressure, toanother reactor for final production of desired products.

Especially desirable as starting feeds are creosotes, or fractionsthereof, at least once refined by hydrogen.

Example 5.Instead of racticing the invention as shown in foregoingexamples, the following procedure may be practiced: instead of treatingthe overall creosote at first, only high boiling fractions may betreated. A creosote, as for instance a high residue creosote, isdistilled to recover the fraction above 355 C. as a residue. The residueis then treated with hydrogen in accordance with foregoing disclosuresfor either refining purposes or for actual production of products of thepresent invention. In the event the residue is merely refined, thetreated residue may be blended with the stripped fractions and furthersubjected to the action of hydrogen for the production of products ofthe present invention.

By the term creosote in the specification and the appended claims is notmeant any specific boiling range material; but included in meaning arematerials of the boiling range of any natural creosote on the market orpossible of manufacture and also shingle stain oils, or the like, andthe refined creosotes.

Aromatic tars of petroleum origin are herein considered the equivalentof creosote because of the low carbon content of said aromatic tars ofpetroleum origin.

A convenient method for evaluating toxicity is in accordance with Methodof Conducting the Tests, page 2, Technical Bulletin No. 346, March,1933, The Efiect of Concentration on the Toxicity of Chemicals to LivingOrganisms." A convenient method for evaluating solvent power is by thewell-known Kauri-Butanol number or the aniline point.

Minor changes may be made without departing from the spirit of theinvention. In the claims affixed to this specification no selection ofany particular modification of the invention is intended to theexclusion of other modifications thereof.

I claim:

1. In the rendering of high temperature coal tar creosote more toxic towood destroying fungi, the process which comprises: subjecting saidcreosote to the action of hydrogen while contacting as catalyticmaterials molybdenum sulfide and tin chloride; carrying on the processat av temperature and pressure of at least 400 C. and 200 atmospheres,respectively; continuing the treatment for such alength of time as toprovide newly formed low boiling fractions boiling at least as low asabout 0.; and fractionating the treated material to separate suflicientfractions boiling below 210 C. to rovide a material as an oil of thewood preserving type boiling not in excess of about 10% at 210 C. havinga toxicity in excess of the parent material.

2. In the rendering of high temperature coal ,tar creosote more toxic towood destroying fungi,

the process which comprises: subjecting said creosote to the action ofhydrogen while contacting as catalytic materials molybdenum sulfide andtin chloride; carrying on the process at a temperature and pressure ofat least 400 C. and 200 atmospheres, respectively; continuing thetreatment for such a length of time as to provide newly formed lowboiling fractions boiling at least as low as about 70 C.; andfractionating from the treated material a relatively low boilingdistillate and a relatively high boiling distillate, said distillatelast named being an oil of the wood preserving type boiling not inexcess of about 10% at 210 C. and being further characterized bytoxicity in excess of its parent material.

JACQUELIN E. HARVEY, JR.

